Patrick O'Keefe1, Frank D Mann2, Sean Clouston2, Stacey Voll3, Graciela Muniz-Terrera4, Nathan Lewis3,5, Linda Wanström6, Scott M Hofer3,1, Joseph L Rodgers7. 1. Department of Neurology, Oregon Health & Science University, Portland, USA. 2. Program in Public Health, Department of Family, Population, and Preventive Medicine, Stony Brook University, New York, USA. 3. Institute on Aging & Lifelong Health, University of Victoria, British Columbia, Canada. 4. Edinburgh Dementia Prevention, University of Edinburgh, UK. 5. Department of Psychology, University of Victoria, British Columbia, Canada. 6. Linköping University, Sweden. 7. Vanderbilt University, Nashville, Tennessee, USA.
Abstract
BACKGROUND: Grip strength is a popular and valuable measure in studies of physical functional capabilities in old age. The influence of historical trends and differential period-specific exposures can complicate the interpretation of biomarkers of aging and health and requires careful analysis and interpretation of aging, birth cohort, and period effects. This study evaluates the effects of aging, period, and cohort on grip strength in a population of adults and older adults. METHODS: We use more than 27 000 observations for individuals at least 50 years of age, born in approximately 1910-1960, from the English Longitudinal Study of Ageing to examine a variety of multilevel and cross-classified modeling approaches to evaluate age, period, and cohort effects. Our results extended Hierarchical Age-Period-Cohort modeling and compared our results with a set of 9 submodels with explicit assumptions to determine the most reliable modeling approach. RESULTS: Findings suggest grip strength is primarily related to age, with minimal evidence of either period and/or cohort effects. Each year's increase in a person's age was associated with a 0.40-kg decrease in grip strength, though this decline differs by gender. CONCLUSIONS: We conclude that as the population ages, grip strength declines at a systematic and predictable rate equal to -0.40 kg per year (approximately -0.50 kg for men and -0.30 kg for women) in residents of England aged 50 and older. Age effects were predominant and most consistent across methodologies. While there was some evidence for cohort effects, such effects were minimal and therefore indicative that grip strength is a consistent physiological biomarker of aging.
BACKGROUND: Grip strength is a popular and valuable measure in studies of physical functional capabilities in old age. The influence of historical trends and differential period-specific exposures can complicate the interpretation of biomarkers of aging and health and requires careful analysis and interpretation of aging, birth cohort, and period effects. This study evaluates the effects of aging, period, and cohort on grip strength in a population of adults and older adults. METHODS: We use more than 27 000 observations for individuals at least 50 years of age, born in approximately 1910-1960, from the English Longitudinal Study of Ageing to examine a variety of multilevel and cross-classified modeling approaches to evaluate age, period, and cohort effects. Our results extended Hierarchical Age-Period-Cohort modeling and compared our results with a set of 9 submodels with explicit assumptions to determine the most reliable modeling approach. RESULTS: Findings suggest grip strength is primarily related to age, with minimal evidence of either period and/or cohort effects. Each year's increase in a person's age was associated with a 0.40-kg decrease in grip strength, though this decline differs by gender. CONCLUSIONS: We conclude that as the population ages, grip strength declines at a systematic and predictable rate equal to -0.40 kg per year (approximately -0.50 kg for men and -0.30 kg for women) in residents of England aged 50 and older. Age effects were predominant and most consistent across methodologies. While there was some evidence for cohort effects, such effects were minimal and therefore indicative that grip strength is a consistent physiological biomarker of aging.
Authors: Andrea R Zammit; Annie Robitaille; Andrea M Piccinin; Graciela Muniz-Terrera; Scott M Hofer Journal: J Gerontol A Biol Sci Med Sci Date: 2019-03-14 Impact factor: 6.053
Authors: Kaare Christensen; Mikael Thinggaard; Anna Oksuzyan; Troels Steenstrup; Karen Andersen-Ranberg; Bernard Jeune; Matt McGue; James W Vaupel Journal: Lancet Date: 2013-07-11 Impact factor: 79.321